8 ARSENATE OF LEAD AGAINST TOBACCO HOENWOEMS. 



lime the mixture lumped out of the gun considerably. On the other 

 hand, the arsenate of lead and ashes made a very even dust, with 

 scarcely any lumping. These two experiments are here shown to 

 emphasize the necessity of applying a thoroughly even dust. A 

 lumpy application is a waste of time and material and will be no 

 more effective than would a perfect application which had been 

 rained upon immediately following the application. 



HOW TO APPLY ARSENATE OF LEAD TO TOBACCO. 



Paris green is generally applied to tobacco by means of a dust 

 gun and without the admixture of a carrier. On the other hand, 

 arsenate of lead must be mixed with a carrier in order to secure an 

 even and thorough distribution. Several carriers have been tested 

 with this insecticide. Finely sifted air-slaked lime, to our surprise, 

 did not dust evenly. Road dust and land plaster proved to be too 

 heavy. The best results were obtained with finely sifted, freshly burned 

 wood ashes. At least an equal bulk of the wood ashes should be used. 

 Mix the arsenate of lead and ashes very thoroughly and apply while 

 there is dew upon the tobacco and when there is no breeze. Even if 

 very dry and finely sifted ashes are used, unsatisfactory results will 

 be obtained unless the application is made with a powerful dust gun. 

 The hand-power dust guns now in general use do not furnish suffi- 

 cient power to make anything like a satisfactory and effective appli- 

 cation. Special guns that will perform satisfactory work are gradu- 

 ally coming on the market. The new guns have a fan with a diame- 

 ter of 8 inches, whereas the old guns have a fan diameter of only 6 

 inches. The new guns have also an auxiliary dust chamber, which 

 is very essential, because the dust containers of the old guns are so 

 small that they have to be refilled five or six times for each acre 

 dusted. Two refillings of the new guns will be sufficient for dusting 

 an acre. 



To secure the best results dust the tobacco when dew is ujDon the 

 plants and when there is no breeze. By reference to Table III we 

 see the comparative results of a good and a poor application of 

 arsenate of lead. The use of a carrier that does not dust evenly, the 

 application of the insecticide when there is too much breeze, and the 

 use of too small a dust gun are all certain to give unsatisfactory 

 results. Avoid these mistakes, and satisfactory results will be secured. 



Thoroughness of application can not be too strongly recommended. 

 When tobacco worms are numerous a poor application of an insecti- 

 cide will miss worms enough to ruin in two days more than enough 

 tobacco to pay for the whole application. Make the application 

 thorough. 



